Easy
15-30 minutes
Genuine Manufacturer Sourced replacement part, this item is sold individually. The Piston/Driver Assembly is the part of the nail gun that drives the nail into the material that is being used. To help extend the life of a pneumatic tool use the specified oil in it daily 4-5 Drops will do every time you use it. The Piston/Driver Assemblies do have a tendency to bend or break if not used correctly or if you are driving nails into extra hard material.
Piston Driver Assembly 647649-00-K
OEM part for: DeWALT, Porter Cable
Part Number: 647649-00-K
$22.39
In Stock
Ships within 1 business day 
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Frequently Purchased Together ?
Compatibility
This part will fit the following 6 machines
DeWALT
D51257 16 Gauge Finish Nailer View Diagrams & Manuals
D51257K Type 1 16 GA Finish Nailer View Diagrams & Manuals
D51257K Type 2 16 GA Finish Nailer View Diagrams & Manuals
Porter Cable
FN250C Type 1 16 Ga. 2-1/2" Finish Nailer Kit View Diagrams & Manuals
FN250C (Type 2) Finish Nailer Power Tool View Diagrams & Manuals
FN250C (Type 3) Finish Nailer Power Tool View Diagrams & Manuals
Show More Compatible Models
This item works with the following types of products:
- Nailer Parts
This part replaces obsolete part #: 647649-00SV, 647649-00
Customer Part Reviews ?
Average Rating (out of 5):
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Fits and works perfect.
Fits and works perfectly in my Porter Cable FN250C, 16Ga.
Just be aware, save the small black ring and white plastic sealer if still intact, or purchased new ones; this is the piston only(had to purchase the white plastic sealer).
Timely delivery.
Anonymous -
April 2, 2022
Verified Purchase
Works like NEW!
The right part at the right price. Saved hundreds by replacing the part by myself instead of just trashing it and getting a new one.
Peter -
February 3, 2022
Verified Purchase
Gracias fue sencillo cambiar la pieza y trabaja muy bien
La pieza de cambio no demoró estuvo en buen tiempo de entrega gracias
Guest -
January 28, 2022
Verified Purchase
Easy repair
The Piston Driver arrived in a timely manner and was spot on. Was using my finish nailer again in less than an hour.
Guest -
April 14, 2020
Verified Purchase
DIY repair
Parts are always available and ship charges are not over priced
David -
April 14, 2020
Verified Purchase
Good parts at a reasonable pricel.
I received the parts in a very timely manner. The parts worked fine. Thanks.
Guest -
October 4, 2019
Verified Purchase
Working Again
I need this part to fix my nail gun great price shipping was not as fast as I'd like but now slow either. Will buy from them again.
Guest -
July 27, 2019
Verified Purchase
Great part, great repair.
Site made it easy to identify exactly what I needed. Got it quickly and it worked perfectly.
Guest -
May 30, 2019
Verified Purchase
Exactly what I needed
Arrived in an expected time period
Colleen -
May 15, 2020
Verified Purchase
ships quick
was the parts I needed thanks
Guest -
July 15, 2019
Verified Purchase
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t days ago
Verified Purchase
eReplacementParts Team
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Questions & Answers ?
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We have a dedicated staff with decades of collective experience in helping customers just like you purchase parts to repair their products.
Does this fit my product?Questions & Answers for Piston Driver Assembly
Porter Cable OEM 647649-00-K does thi part work with porter cable fn250b ? thank youBarcelona
barcelona
for model number porter cable fn250b
asked on 2023-03-15
Hi Barcelona,
Thank you for your question. This would not be the correct piston driver assembly for your nail gun.
The part number listed under your model number for the driver maintenance kit is 904950. The kit includes the piston, the ring, the driver, the bumper, the gasket, the lubricant, and the hex key wrenches. If you would like to place an order for it, please call our customer service line and anyone will be happy to assist you. We look forward to hearing from you!
eReplacementParts Team March 15, 2023
does this driver assembly work with porter cable fn250b ?
barcelona
for model number porter cable fn250b
asked on 2023-03-15
Hello Barcelona, Thank you for your inquiry. We have researched the model you have provided and do not show this part as compatible. The compatible part number is 904950, which includes the piston, ring, driver, bumper, gasket, lubricant, and hex key wrenches. We hope this helps you.
eReplacementParts Team March 15, 2023
Does the seal ring come with the piston driver when purchasing
Jerry
for model number FN250C
asked on 2023-01-05
Hello Jerry, Thank you for the question. The Seal O-Ring Part Number: 647951-00 is sold separate from the Piston. Thank you for your inquiry, good luck with this repair!
eReplacementParts Team January 05, 2023
Customer Repair Instructions ?
All our customer repair instructions are solicited directly from other customers just like you who have purchased and replaced this exact part.
Piston driver assembly snapped, and ring seal broke within cylinder - nailier inoperaboe
Robert - August 19, 2016
👍 3 of 3 people found this instruction helpful
Tool Type
Nailer
Difficulty
Medium
Time
15-30 minutes
Tools Used
Nutdriver
1. Using hex wrench, remove cap from nailer
2. Remove cylinder/driver assembly from nailer housing
3. Remove broken driver assembly & seal from cylinder
4. Place new O-Ring (black) around new driver assembly
5. Wrap new seal (white) around new driver assembly
6. Insert new driver assembly/seal into cylinder
7. Insert cylinder/driver assembly into nailer housing
8. Reattach cap using hex wrench.
9. Ensure that driver is aligned within nose assembly
2. Remove cylinder/driver assembly from nailer housing
3. Remove broken driver assembly & seal from cylinder
4. Place new O-Ring (black) around new driver assembly
5. Wrap new seal (white) around new driver assembly
6. Insert new driver assembly/seal into cylinder
7. Insert cylinder/driver assembly into nailer housing
8. Reattach cap using hex wrench.
9. Ensure that driver is aligned within nose assembly
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Nail driver was bent
Samuel - January 22, 2019
👍 1 of 1 people found this instruction helpful
Tool Type
Nailer
Difficulty
Medium
Time
15-30 minutes
Tools Used
, Allen wrenches
Parts Used
Took top off gun removed the cylinder and the shooting pin. Replace pin and put it back together
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Nail driver and piston ass'y busted up.
Lanier - April 19, 2023
Tool Type
Nailer
Difficulty
Medium
Time
1-2 hours
Tools Used
Screwdriver, Pliers, Power Drill, dental pick to remove o-rings
Parts Used
Disassemble. Remove and replace trigger ass'y. Replace Nail driver and all O-rings. Use petrolatum jelly as lubricant for internal parts. Use Rem Oil w/Teflon lubricant spray for Nailer slide tracks. Assemble all and replace body pin O-rings.
The 16 Ga Finish Nailer works like brand new. So pleased. Could have saved money buying the O-rings local. Cost about $70.00 on a $300 Tool.
The 16 Ga Finish Nailer works like brand new. So pleased. Could have saved money buying the O-rings local. Cost about $70.00 on a $300 Tool.
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Piston rod broken
John - September 18, 2021
Tool Type
Nailer
Difficulty
Easy
Time
Less than 15 minutes
Tools Used
, Allen wrench
Parts Used
Removed screws replaced broken parts.
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Nail driving pin broke and ruined the piston cylinder
Justin - March 31, 2021
Tool Type
Nailer
Difficulty
Medium
Time
15-30 minutes
Tools Used
Screwdriver, Allen wrench
1. Removed the four bolts holding on the rear cap.
2. Removed internals.
3. Installed new internals with a light coating of oil.
4. Reinstalled rear cap with new gasket.
2. Removed internals.
3. Installed new internals with a light coating of oil.
4. Reinstalled rear cap with new gasket.
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broken piston driver
COLIN - March 16, 2019
Tool Type
Nailer
Difficulty
Medium
Time
30-60 minutes
Tools Used
Screwdriver, Pliers, allen wrench
Watched "how to repair nailer" on utube.
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The piston broken
Rafael - December 1, 2017
Tool Type
Nailer
Difficulty
Easy
Time
Less than 15 minutes
Tools Used
Screwdriver
Parts Used
I removed four screws on the back of the finish nail gun ,took the cylinder and replace the piston, I put back the screws and started to work.
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Driver was bent
Wade - August 4, 2017
Tool Type
Nailer
Difficulty
Easy
Time
Less than 15 minutes
Tools Used
, Allen wrench
Parts Used
Removed the four screws holding the cap.
Removed the bent driver and oiled the inside of the gun
Installed the new driver
Replace the cap with the four screws
Removed the bent driver and oiled the inside of the gun
Installed the new driver
Replace the cap with the four screws
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The piston driver bent and the seal was chewed up.
Steven - July 26, 2017
Tool Type
Nailer
Difficulty
Easy
Time
Less than 15 minutes
Tools Used
, Hex wrench
1. Removed the head of the nailer (4 hex screws).
2. Removed the bent piston driver.
3. Installed the new o-ring and the seal onto the new driver.
4. Reassembled the tool.
2. Removed the bent piston driver.
3. Installed the new o-ring and the seal onto the new driver.
4. Reassembled the tool.
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Piston driver broke off.
Marcos - June 1, 2017
Tool Type
Nailer
Difficulty
Easy
Time
Less than 15 minutes
Tools Used
, Allen wrenches (comes with the tool)
Parts Used
1. Remove 4 screws from the back of side of the gun.
2. Pull out the cover and the o-ring.
3. Pull the broken piston.
4. Install the new one thru the driving hole.
5. Place the cover back in place (cover is spring loaded) need to keep the pressure on it.
6. Align the seal or o-ring the right way.
7. Drive the 4 screws in and call it the day,
2. Pull out the cover and the o-ring.
3. Pull the broken piston.
4. Install the new one thru the driving hole.
5. Place the cover back in place (cover is spring loaded) need to keep the pressure on it.
6. Align the seal or o-ring the right way.
7. Drive the 4 screws in and call it the day,
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Our customer service team are at the ready daily to answer your part and product questions. We have a dedicated staff with decades of collective experience in helping customers just like you purchase parts to repair their products.
All our part reviews are solicited directly from other customers who have purchased this exact part. While we moderate these reviews for profanity, offensive language or personally identifiable information, these reviews are posted exactly as submitted and no alterations are made by our team.
All our customer repair instructions are solicited directly from other customers just like you who have purchased and replaced this exact part. While we moderate these reviews for profanity, offensive language or personally identifiable information, these reviews are posted exactly as submitted and no alterations are made by our team.
Based on data from past customer purchasing behaviors, these parts are most commonly purchased together along with the part you are viewing. These parts may be necessary or helpful to replace to complete your current repair.
All our installation videos are created and produced in collaboration with our in-house repair technician, Mark Sodja, who has helped millions of eReplacementParts customers over the last 13 years repair their products. Mark has years of experience in selling and repairing both commercial and residential products with a specialty in gas-powered equipment.
This data is collected from customers who submitted a repair instruction after replacing this exact part. Customers can rate how easy the repair was to complete and how long it took. We aggregate this data to provide a repair rating that allows customers to quickly determine the difficulty and time needed to perform their own repair.
